Roller, separation device, image reading apparatus, and recording apparatus

ABSTRACT

A roller includes a shaft, and an elastic body portion that is provided on an outer peripheral surface of the shaft, in which the elastic body portion includes an inner peripheral portion which becomes a shaft side, an outer peripheral portion which becomes an outer side with respect to the inner peripheral portion, a plurality of first connection portions which connect the inner peripheral portion and the outer peripheral portion, and a plurality of second connection portions which are provided in a space portion between the adjacent first connection portions and which partition the space portion into one side and the other side of the roller in the axial direction, and in which the first connection portion is inclined in the same direction in a peripheral direction with respect to a radial direction of the roller.

BACKGROUND 1. Technical Field

The present invention relates to a roller used for transporting, or thelike a medium such as a paper, a separation device including the roller,an image reading apparatus such as a scanner, and a recording apparatus.

2. Related Art

In order to secure a transport performance for various media, a surfaceof a roller is in contact with a surface of the medium and transportsthe medium, it is desirable that this kind of rollers is elasticallyslightly crushed a surface thereof which is brought into contacttherewith and the contact area between the surface of the medium and thesurface of the roller increases. In the related art, the crush isrealized using a foamed rubber material as a material for the roller.

In addition to the foamed rubber material, an elastomer is used torealize the crush (JP-A-2008-241739 or the like).

However, in order to secure the transport performance of the roller bythe foamed rubber material, a high-quality material is required,resulting in a problem of high cost. In addition, cracks are likely tobe generated from the foamed portion as a starting point over time, andwhen repeated deformation is added, it is difficult for the shapethereof to be returned to the original shape thereof, resulting in aproblem that the durability of the roller is lowered.

In a roller using an elastomer other than the foamed rubber material,although there is no problem that cracks are likely to be generated froma foamed portion such as a foamed rubber material as a starting point,since the elastomer generally has a rubber hardness higher than that ofa foamed rubber material, in order to secure the transport performanceof the roller due to the crush, it is difficult to select a propermaterial and degrees of freedom of selection is lowered. As a result,there is a problem of high cost.

In addition, there are the following problems from the manufacturingaspect of the roller.

Generally, the roller is manufactured by pouring a raw material into amold and filling the mold with the raw material, as in insert molding orthe like. In the insert molding or the like, although it is necessary tosecure fluidity when pouring and filling the mold with the raw materialthereof, even in a structure in which the roller penetrates from oneside surface to the other side surface in the axial direction thereof,it is difficult to secure the fluidity and the time required forcompletion of filling is likely to be long. Therefore, heat history atthe time of curing the raw material is likely to be changed according tolocations, and there is a problem that a shape accuracy of an outerperipheral surface of the roller as the final molded product is likelyto be reduced.

SUMMARY

An advantage of some aspects of the invention is to structurally realizecrush of a surface at the time of transporting for securing a transportperformance of a roller, not by selection of materials. In addition,even in a case where the roller is manufactured by pouring and filling amold with the raw material as in insert molding or the like, thereduction of a shape accuracy of an outer peripheral surface of theroller as the final molded product can be easily suppressed.

According to an aspect of the invention, there is provided a rollerincluding: a shaft, and an elastic body portion that is provided on anouter peripheral surface of the shaft, in which the elastic body portionincludes an inner peripheral portion which becomes a shaft side, anouter peripheral portion which becomes an outer peripheral side withrespect to the inner peripheral portion, a plurality of first connectionportions which connect the inner peripheral portion and the outerperipheral portion to each other, and a plurality of second connectionportions which are provided in a space portion between the adjacentfirst connection portions to each other and which partitions the spaceportion into one side and the other side of the roller in a shaftmounting direction, and in which the first connection portion isinclined in the same direction in a circumferential direction withrespect to a radial direction of the roller.

Here, in this configuration, the term “inclined” is used as a meaningincluding a structure in which the first connection portion has a curvedshape and is inclined with respect to the radial direction in a sideview in addition to the structure in which the first connection portionhas a linear shape and is inclined with respect to the radial directionfrom a center of the roller in a side view of the roller.

In this configuration, since the plurality of first connection portionsare inclined in the same direction in the circumferential direction withrespect to the radial direction from the center of the roller, when theroller is pressed against the medium such as paper and exerts atransporting action, the roller is easily crushed by the inclinedstructure of the first connection portion, and thus the contact area canincrease. Supplementally, even if the elastic body portion is made of amaterial having a high rubber hardness, it can be easily crushed by theinclined structure and the contact area can increase.

A mechanism of the crush of the roller in this configuration will bedescribed below.

When the roller is pressed against the medium and a pressing forcedirected toward the center of the roller is applied to the medium, aforce (shearing) in the opposite direction parallel to the pressingdirection respectively acts on both the connection portion of the firstconnection portion with the inner peripheral portion and the connectionportion of the first connection portion with the outer peripheralportion. If the first connection portion is a rigid body, although thefirst connection portion will mainly be “swung” by the force, since thefirst connection portion is also an elastic body in this configuration,the first connection portion can “shrink in the longitudinal direction”by the force. In other words, the first connection portion of thisconfiguration can “shrink in the longitudinal direction” while“swinging” when a pressing force is applied to the roller. This crushcan be realized by this behavior.

Accordingly, it is possible to easily structurally realize the crush ofthe roller surface at the time of transport for securing the transportperformance of the roller not by selection of materials.

In addition, in a case of manufacturing the roller by the insert moldingor the like, the fluidity of the raw material is likely to be secured byproviding the second connection portion, decrease in the shape accuracyof the outer peripheral surface of the roller as a final molded productcan be suppressed.

In the roller, the second connection portion may be inclined withrespect to a surface orthogonal to the shaft mounting direction of theroller, and inclination directions of adjacent second connectionportions to each other via the first connection portion may be oppositeto each other.

Here, “inclination” in this specification is used as a meaning for astructure having a curved shape and being inclined with respect to thesurface in longitudinal sectional view in addition to the structurehaving a linear shape and being inclined with respect to the surface inthe longitudinal sectional view of the second connection portion.

In this configuration, since the second connection portion is inclinedwith respect to a surface orthogonal to the shaft mounting direction ofthe roller, when the pressing force is applied to the roller, the secondconnection portion can be “shrunk in the longitudinal direction” while“swinging” as in the first connection portion.

Further, since the inclination directions of the adjacent secondconnection portions to each other via the first connection portion areopposite to each other, the swinging between the adjacent secondconnection portions is performed to have a relationship of cancelingeach other via the first connection portion, so that shrinkagedeformation in the longitudinal direction is generated exclusively andcrush of the roller can be achieved in a well-balanced manner. In otherwords, since the inclination directions of the adjacent secondconnection portions via the first connection portion are opposite toeach other, forces in the width direction (axial direction) of thedevice generated by swinging between the second connection portions isperformed to have a relationship of canceling each other and the crushof the roller can be achieved in a well-balanced manner.

In the roller, a recessed portion on one side that can be formed on oneside of the roller in the shaft mounting direction and the recessedportion on the other side that can be formed on the other side with thesecond connection portion as a boundary may be formed so as to besymmetrical with respect to a center surface orthogonal to the shaftmounting direction.

In this configuration, since the recessed portion on the one side thatcan be formed on one side of the roller in the shaft mounting directionand the recessed portion on the other side that can be formed on theother side with the second connection portion as a boundary are formedso as to be symmetrical with respect to the center surface orthogonal tothe shaft mounting direction, and further, this symmetrical structurebecomes an opposite structure in the adjacent peripheral directions toeach other, the crush of the roller can be realized in a morewell-balanced manner when the pressing force is applied to the roller.

In the roller, the constituent material of the elastic body portion maybe a non-foamed material.

In this configuration, since the constituent material of the elasticbody portion is a non-foamed material, there is no problem that a crackis generated over time from the foamed portion as a starting point.

In the roller, the elastic body portion may include an inner layerportion that becomes the shaft side, and an outer layer portion thatbecomes a side which is in contact with the medium, and the inner layerportion includes the first connection portion, the second connectionportion, the inner peripheral portion, and the outer peripheral portion.

In this configuration, the elastic body portion of the roller can bealso applied to a two-layered structure and the effect described abovecan be obtained.

In addition, in the two-layered structure, when the fluidity of the rawmaterial is lowered at the time of manufacturing by insert molding orthe like, although the problem that the shape accuracy of the outerlayer portion of the roller as the final molded product is likely to belowered is likely to be generated, in this configuration, since thefluidity can be improved by the second connection portion, generation ofthe problem can be suppressed.

In the roller, an inclination angle of the first connection portion maybe 30° or more with respect to the radial direction of the roller.

In this configuration, since the inclination angle of the firstconnection portion is 30° or more with respect to the radial directionof the roller, the crush of the roller can be stably realized.

In the roller, an inclination angle of the second connection portion maybe 60° or less with respect to the axial direction of the roller.

In this configuration, since the inclination angle of the secondconnection portion is 60° or less with respect to the axial direction ofthe roller, the crush of the roller can be stably realized.

In the roller, the numbers of the recessed portion on the one side thatcan be formed on one side in the axial direction of the roller and therecessed portion on the other side that can be formed on the other sidewith the second connection portion as a boundary may be 6 or morerespectively.

In this configuration, since the number of the recessed portion on theone side that can be formed on the one side in the axial direction ofthe roller and the recessed portion on the other side that can be formedon the other side with the second connection portion as a boundary is inthe range described above, the crush of the roller can be stablyrealized.

According to another aspect of the invention, there is provided aseparation device including: a feeding roller, and a retard roller thatforms a pair with the feeding roller, separates media other than amedium to be transported from a bundle of media, and returns the mediato an upstream side, in which the retard roller is the roller describedabove.

In this configuration, an effective separation device can be realized bythe pair of the feeding roller and the retard roller.

In the separation device, an inclination direction of the firstconnection portion may be formed such that, when the roller receives apressing force from the medium, a swinging direction with the connectionportion with the inner peripheral portion of the first connectionportion as a supporting point becomes a direction of returning themedium to the upstream side.

In this configuration, when the retard roller receives a pressing forcefrom the medium, although the first connection portion slightly swings,since the swinging thereof can be used for returning the medium to theupstream, an effective separation device can be realized.

According to still another aspect of the invention, there is provided animage reading apparatus including: a reading portion that reads imageinformation of a medium, and a roller that is provided in a mediumtransport path which passes through a reading execution region of thereading portion and that applies a feeding force to the medium, in whichthe roller has a structure in which a contact surface between the rollerand the medium is elastically crushed when pressed against the medium,and at least one of the rollers is the roller described above.

In this configuration, the effects described above can be obtained asthe image reading apparatus.

According to still another aspect of the invention, there is provided arecording apparatus including: a recording portion, and a roller that isprovided in a medium transport path passing through a recordingexecution region of the recording portion and applies a feeding force tothe medium, in which the roller has a structure in which a contactsurface thereof is elastically crushed when pressed against the medium,and at least one of the rollers is the roller described above.

In this configuration, the effects described above can be obtained asthe recording apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a perspective view illustrating an outer appearance of animage reading apparatus according to Embodiment 1 of the invention.

FIG. 2 is a cross-sectional view of a main portion illustrating theimage reading apparatus according to Embodiment 1 of the invention.

FIG. 3 is a cross-sectional view of a main portion illustrating aseparation device according to Embodiment 2 of the invention.

FIG. 4 is a perspective view illustrating a roller according toEmbodiment 3 of the invention.

FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4illustrating the roller according to Embodiment 3 of the invention.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4illustrating the roller according to Embodiment 3 of the invention.

FIG. 7 is a side view illustrating the roller according to Embodiment 3of the invention.

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7illustrating the roller according to Embodiment 3 of the invention.

FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 7illustrating the roller according to Embodiment 3 of the invention.

FIG. 10 is an explanation view illustrating a comparison between anaspect of flow of the raw material during the insert molding of theroller according to Embodiment 3 of the invention and an example of therelated art having a penetration portion in an axial direction.

FIG. 11 is a graph illustrating a relationship between the number ofcompressions and the deformation rate due to the difference in rawmaterials.

FIG. 12A is a side view illustrating a state where an inclination angleof the first connection portion representing the roller according toEmbodiment 3 of the invention is 60°.

FIG. 12B is a side view illustrating a state where the inclination angleof the first connection portion representing the roller according toEmbodiment 3 of the invention is 45°.

FIG. 12C is a side view illustrating a state where the inclination angleof the first connection portion representing the roller according toEmbodiment 3 of the invention is 30°.

FIG. 13A is a side view illustrating a state where an inclination angleof the second connection portion representing the roller according toEmbodiment 3 of the invention is 30°.

FIG. 13B is a side view illustrating a state where the inclination angleof the second connection portion representing the roller according toEmbodiment 3 of the invention is 45°.

FIG. 13C a side view illustrating a state where the inclination angle ofthe second connection portion representing the roller according toEmbodiment 3 of the invention is 60°.

FIG. 14A is a side view illustrating a case where the number of arecessed portion on one side and the number of the recessed portion onthe other side illustrating the roller according to Embodiment 3 of theinvention is 6.

FIG. 14B is a side view illustrating a case where the number of therecessed portion on the one side and the number of the recessed portionon the other side illustrating the roller according to Embodiment 3 ofthe invention is 8.

FIG. 14C is a side view illustrating a case where the number of therecessed portion on the one side and the number of the recessed portionon the other side illustrating the roller according to Embodiment 3 ofthe invention is 12.

FIG. 15A is a side view illustrating a modification example in which ashape of the first connection portion representing the roller accordingto Embodiment 3 of the invention is different.

FIG. 15B is a side view illustrating a modification example in which adisposition of a recessed portion on one side and the recessed portionon the other side representing the roller according to Embodiment 3 ofthe invention is different.

FIG. 16A is a longitudinal sectional view illustrating an example of ajunction structure of an inner layer portion and an outer layer portionrepresenting the roller according to Embodiment 3 of the invention.

FIG. 16B is a longitudinal sectional view illustrating another exampleof a junction structure of the inner layer portion and the outer layerportion representing the roller according to Embodiment 3 of theinvention.

FIG. 16C is a longitudinal sectional view illustrating still anotherexample of a junction structure of the inner layer portion and the outerlayer portion representing the roller according to Embodiment 3 of theinvention.

FIG. 17A is a longitudinal sectional view illustrating still anotherexample of a junction structure of the inner layer portion and the outerlayer portion representing the roller according to Embodiment 3 of theinvention.

FIG. 17B is a longitudinal sectional view illustrating still anotherexample of a junction structure of the inner layer portion and the outerlayer portion representing the roller according to Embodiment 3 of theinvention.

FIG. 17C is a longitudinal sectional view illustrating still anotherexample of a junction structure of the inner layer portion and the outerlayer portion representing the roller according to Embodiment 3 of theinvention.

FIG. 18 is a longitudinal sectional view illustrating still anotherexample of a junction structure of the inner layer portion and the outerlayer portion representing the roller according to Embodiment 3 of theinvention.

FIG. 19 is a perspective view illustrating a roller according toEmbodiment 4 of the invention.

FIG. 20 is a side view illustrating a roller according to anotherembodiment of the invention.

FIG. 21 is a longitudinal sectional view illustrating a roller accordingto still another embodiment of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First, as an image reading apparatus of the invention, using an exampleof the continuous automatic feeding type image scanner according toEmbodiment 1 illustrated in FIGS. 1 and 2, an outline of the overallconfiguration of the image reading apparatus and a configuration of amedium transport path will be explained. Next, as a separation device ofthe invention, using an example of a separation device according toEmbodiment 2 illustrated in FIG. 3 mounted on the image readingapparatus, a configuration of the separation device and an outline of aseparation action thereof will be explained.

Next, using an example of a roller according to Embodiment 3 illustratedin FIGS. 4 to 18, which can be applied to a retard roller of theseparation device, a configuration of the roller of the invention andmolding and an action thereof will be specifically described.Furthermore, by picking a roller having a somewhat differentconfiguration from the roller according to the Embodiment 3 as a rolleraccording to Embodiment 4 of the invention, a structure of the rollerand an action thereof will be described focusing on the differences fromEmbodiment 3.

Finally, a configuration of a roller according to another embodiment ofthe invention, which is different in configuration from Embodiments 3and 4 and an embodiment in which the roller of the invention is appliedto the recording apparatus will be described.

Embodiment 1 (1) Outline of Overall Configuration of Image ReadingApparatus (See FIGS. 1 and 2)

The illustrated image reading apparatus 10 includes a lower unit 12, anupper unit 14, a cover portion 16, and a discharge tray 18. In addition,although not illustrated, the upper unit 14 has a rotation supportingpoint at an end portion on the downstream side in the medium transportdirection A of the lower unit 12, and is rotatably attached to the lowerunit 12 via the rotation supporting point.

In addition, although not illustrated, on an upper portion of a rearsurface side of the lower unit 12, the same rotation supporting point isalso provided, and the cover portion 16 is rotatably attached to thelower unit 12 via the rotation supporting point. The cover portion 16can take a non-feeding state (not illustrated) of covering the upperportion of the upper unit 14 and the feeding port 20 and a feedablestate of opening the feeding port 20 by rotating to the rear surfaceside of the device as illustrated in FIG. 1. Then, when the coverportion 16 is in a feedable state as illustrated in FIG. 1, the backsurface of the cover portion 16 is exposed and functions as a mediummounting portion 16 a on which the medium P is mounted.

In addition, a discharge port 24 for discharging the medium P isprovided on the front surface side of the device of the lower unit 12.In addition, the lower unit 12 includes a discharge tray 18 that can bedrawn out from the discharge port 24 toward the front surface side ofthe device. The discharge tray 18 is attached to the lower unit 12 so asto be capable of taking a state (not illustrated) of being accommodatedin a bottom portion of the lower unit 12 and a state (see FIG. 1) ofbeing drawn to the front surface side of the device. In addition, thedischarge tray 18 is configured by connecting a plurality of traymembers, and the drawing length from the discharge port 24 can beadjusted with respect to the size of the medium P to be discharged.

(2) Configuration of Medium Transport Path in Image Reading Apparatus

Next, a configuration of a medium transport path 26 in the image readingapparatus 10 will be described with reference to FIG. 2. In FIG. 2, onlythe outer shells of the lower unit 12 and the upper unit 14 areillustrated by virtual lines. In addition, in FIG. 2, the bold solidline denoted by reference symbol P indicates a trajectory of thetransport of the medium P transported along the medium transport path 26in the image reading apparatus 10. The multi-fed medium P which is notillustrated is configured so as to be separated by the separation device60, which will be described below, and be separated from the medium Ptransported toward the reading portion 52 and remain at a separationposition.

The bundle G of the medium whose a leading end is inserted into thefeeding port 20 is set in a state of being supported by the mediummounting portion 16 a described above as indicated by a one-dot chainline in FIG. 2. In addition, a placing portion detection sensor 28 isprovided on the medium mounting portion 16 a. The placing portiondetection sensor 28 is configured with a contact type sensor having alever or the like, an optical non-contact type sensor, or the like, asan example and when the medium P is set on the medium mounting portion16 a, the placing portion detection sensor 28 transmits the detectionsignal thereof to the control unit 30 indicated by a virtual line inFIG. 2.

In addition, as illustrated in FIG. 1, a pair of edge guides 22 isprovided on the medium mounting portion 16 a. The edge guides 22 areconfigured to be movable in mutually approaching directions and inmutually spaced directions in the device width direction X. When themedium P is set on the medium mounting portion 16 a, the guide surfaceof the edge guide 22 is configured so that the guide surface is incontact with the left and right side portions of the medium P in thedevice width direction X, and the position of the medium P in the devicewidth direction X is restricted, and the feeding of the medium P to thereading portion 52 is guided. The edge guide 22 in FIG. 1 indicates astate where it is most distant in the device width direction X, that is,in the width direction of the medium P.

The medium P located at the lowermost position among the bundle G of themedium set on the medium mounting portion 16 a is fed toward thedownstream side in the medium transport direction A by a feeding roller34 driven to rotate by a feeding driving motor (not illustrated).Although not illustrated, two feeding rollers 34 are provided at aninterval in the device width direction X as an example. In addition, anouter peripheral surface of the feeding roller 34 is configured to bemade of a high friction material (for example, synthetic rubber,elastomer, or the like).

In addition, in FIG. 2, the leading end of the bundle of documentsindicated by reference symbol G is held at the feed waiting positionillustrated in FIG. 2 by a stopper (not illustrated) before feedingstart and entrance thereof between the feeding roller 34 and a retardroller 36 to be described below is restricted.

In addition, a retard roller 36, which is a constituent member of theseparation device 60 described below, is provided together with thefeeding roller 34 at a position facing the feeding roller 34. As withthe feeding roller 34, two retard rollers 36 are also provided in thedevice width direction X as an example. The retard roller 36 is providedin a state of being urged toward the feeding roller 34 by urging means(not illustrated).

In addition, the retard roller 36 is configured to be driven to rotatein a direction C opposite to the rotation direction B of the feedingroller 34 by a transport driving motor (not illustrated), a torquelimiter 40 is provided on the retard roller 36, and via the torquelimiter 40, the retard roller 36 is configured to receive a drivingtorque of a transport driving motor (not illustrated).

A first medium detection sensor 42 for detecting the feeding of themedium P is provided at a downstream position of the feeding roller 34and the retard roller 36 in the medium transport path 26. Although notillustrated, the first medium detection sensor 42 is disposed as anexample within the transport region of the maximum size medium P thatcan be fed in the device width direction X of the medium transport path26. The first medium detection sensor 42 is configured as an example byan optically non-contact type sensor including a light emitting unit 42a and a light receiving unit 42 b which are disposed at positions facingeach other with the medium transport path 26 interposed therebetween.When the medium P is transported to the medium transport path 26, themedium P blocks the detection light from the light emitting unit 42 a,so that feeding of the medium P is detected and the detection signal istransmitted to the control unit 30.

On the downstream side of the first medium detection sensor 42 in themedium transport direction A in the medium transport path 26, amulti-feed detection sensor 44 for detecting multi-feeding of the mediumP is disposed in the medium transport region in the device widthdirection X, as an example. The multi-feed detection sensor 44 includesa speaker portion 44 a and a microphone portion 44 b and is configuredto oscillate an ultrasonic wave from the speaker portion 44 a toward themedium P passing through the medium transport path 26 and to detectreflected sound from the medium P by the microphone portion 44 b. Inaddition, in the present embodiment, the multi-feed detection sensor 44is configured to be capable of detecting not only the multi-feeding ofthe medium P but also the type of the medium P such as the thickness ofthe medium P, based on the frequency of reflected sound.

At the downstream position of the multi-feed detection sensor 44 in themedium transport direction A in the medium transport path 26, transportroller pair 46 is provided, which is configured with a transport drivingroller 46 a and a transport driven roller 46 b. In addition, a secondmedium detection sensor 48 configured with a contact type sensor havinga lever is provided at a downstream position of the transport rollerpair 46 in the medium transport direction A, as an example.

At the downstream position of the second medium detection sensor 48 inthe medium transport direction A, there is provided a reading portion 52that reads the image expressed on the medium P as image information. Thereading portion 52 includes a first reading unit 52A provided to thelower unit 12 so as to face a first surface that is a lower surface ofthe medium P transported along the medium transport path 26, and asecond reading unit 52B provided in the upper unit 14 so as to face asecond surface that is an upper surface of the medium P to betransported along a medium transport path 26. The first reading unit 52Aand the second reading unit 52B are configured as a contact type imagesensor module (CISM) as an example.

The medium P from which the image represented on at least one of thefirst surface and the second surface is read by the reading portion 52is transported to a discharge roller pair 54 positioned at thedownstream position of the reading portion 52 in the medium transportdirection A. The discharge roller pair 54 is configured by including adischarge driving roller 54 a and a discharge driven roller 54 b, andthe medium P is nipped by the discharge roller pair 54 configured asdescribed above and discharged from the discharge port 24 to theoutside.

The transport driving roller 46 a of the transport roller pair 46 andthe discharge driving roller 54 a of the discharge roller pair 54 may bedriven so as to rotate using a single motor as a common drive source, ormay be rotationally driven separately using separate motors.

The image reading apparatus 10 according to the embodiment of theinvention includes the reading portion 52 described above that readsimage information of the medium P, and the various rollers 34, 36, 46,54, and the like described above that apply a feeding force to a mediumP provided in the medium transport path 26 that passes through thereading execution region of the reading portion 52. These rollers 34,36, 46, 54, and the like have a structure in which the contact surface Sis elastically crushed when pressed against the medium P.

At least one of these rollers 34, 36, 46, 54 and the like is configuredwith the roller 1 of the embodiment according to the invention whichwill be described below. In the present embodiment, the retard roller 36is configured by the roller 1 according to the embodiment of theinvention.

Embodiment 2 (1) Configuration of Separation Device (See FIG. 3)

The illustrated separation device 60 includes a feeding roller 34, and aretard roller 36 which forms a pair with the feeding roller 34,separates the medium P other than the medium P transported from thebundle G of the medium, and returns the medium P to the upstream, andthe retard roller 36 is configured with the roller 1 of the embodimentaccording to the invention.

The roller 1 of the embodiment according to the invention includes ashaft 62, and an elastic body portion 64 provided on the outerperipheral surface of the shaft 62. The elastic body portion 64 of theroller 1 is configured by including an inner peripheral portion 66 whichis a side of the shaft 62, an outer peripheral portion 68 which is theouter peripheral side with respect to the inner peripheral portion 66, aplurality of first connection portions 70 which connect the innerperipheral portion 66 and the outer peripheral portion 68 to each other,and a plurality of second connection portions 72 which are provided inthe space portion 80 between the adjacent first connection portions 70and 70 and partitions the space portion 80 into an X1 side and the otherX2 side in the axial direction X of the roller 1 (the same sign asdevice width direction X is used).

In addition, the first connection portion 70 is provided in a state ofbeing inclined in the same direction in the circumferential direction Ewith respect to the radial direction D of the roller 1.

As illustrated in FIG. 3, in this embodiment, the inclination directionof the first connection portion 70 is formed such that, when the roller1 receives the pressing force F from the medium P, the swingingdirection with the connection portion Ji as a supporting point when theconnection portion of the inner peripheral portion 66 of the firstconnection portion 70 is referred to as Ji and the connection portionwith the outer peripheral portion 68 of the first connection portion 70is referred to as Jo becomes a direction R of returning the medium P tothe upstream side in the medium transport direction A. It is a matter ofcourse that the swinging direction with the connection portion Ji as asupporting point may be attached so as to be opposite to the direction Rof returning the medium P to the upstream side in the medium transportdirection A.

In addition, in the present embodiment and Embodiment 3 to be describedbelow, the elastic body portion 64 further includes an inner layerportion 74 which is a side of the shaft 62, and an outer layer portion76 which is the side in contact with the medium P, and configurationsincluding the first connection portion 70, the second connection portion72, the inner peripheral portion 66, and the outer peripheral portion 68which are described above are adopted to the inner layer portion 74among the inner layer portion 74 and the outer layer portion 76.

In the present embodiment, the outer layer portion 76 is configured asan example with a high friction material such as a synthetic rubber, anelastomer, or the like, similarly to the feeding roller 34 describedabove.

(2) Separation Action of Separation Device (See FIG. 3)

Next, the separation action of the medium P by the separation device 60described above will be explained separately as (A) a basic separationaction and (B) a specific separation action obtained by the roller 1according to the embodiment of the invention.

(A) Basic Separation Action

When the rotational torque received from the feeding roller 34 describedabove exceeds the limit torque of the torque limiter 40, the retardroller 36 is disconnected from a driving system of a transport drivingmotor (not illustrated) that drives the retard roller 36 by the torquelimiter 40, follows the feeding roller 34, and rotates in the clockwisedirection as indicated by the solid arrow C in FIG. 3.

When the feeding of the medium P is started and a plurality of sheets ofmedium P enter between the feeding roller 34 and the retard roller 36,the retard roller 36 does not receive the rotational torque from thefeeding roller 34, follows the feeding roller 34, and thus rotationthereof is stopped. The retard roller 36 receives the driving force fromthe transport driving motor via the torque limiter 40 and startsrotation in the opposite direction (counterclockwise direction asindicated by a broken arrow R in FIG. 3) to the feeding roller 34.

Accordingly, the upper medium P to be prevented from the multi-feeding,excluding the lowermost medium P to be fed, cannot receive the transportforce for advancing to the downstream side in the medium transportdirection A, and is returned to the upstream side in the mediumtransport direction A due to a rotation of the retard roller 36, and themulti-feeding of the medium P is prevented. Since the lowermost medium Pto be fed is in direct contact with the feeding roller 34, the lowermostmedium P is transported to the downstream side in the medium transportdirection A by a transport force received from the feeding roller 34.

(B) Specific Separation Action

Before the medium P is supplied between the feeding roller 34 and theretard roller 36, the feeding roller 34 and the retard roller 36 are incontact with each other. When a feeding force acts on the lowermostsurface medium P of the medium bundle G set on the medium mountingportion 16 a by the rotation of the feeding roller 34, a plurality ofsheets of medium P enter between the feeding roller 34 and the retardroller 36.

Since the retard roller 36 is not in contact with the feeding roller 34by the medium P as described above, the driven rotation in the clockwisedirection is stopped as indicated by the solid arrow C in FIG. 3, andthe reverse rotation is started by own driving force thereof (in acounterclockwise direction as indicated by a broken arrow R in FIG. 3),and returns the two or more media P from the lowermost surface to theupstream in the medium transport direction A.

In the retard roller 36 to which the roller 1 according to theembodiment of the invention is applied, the moment when the medium Penters between the feeding roller 34 and the retard roller 36, thepressing force F acts from the medium P toward the retard roller 36 sothat the outer peripheral surface of the retard roller 36 is slightlycrushed.

In addition, when the outer peripheral surface of the retard roller 36is crushed, although the first connection portion 70 slightly swingsaround the connection portion Ji with the inner peripheral portion 66 asa supporting point, when inclination direction thereof is a directionillustrated in FIG. 3, a slight rotation in the counterclockwisedirection in FIG. 3 occurs instantaneously due to the swing. Themomentary rotation contributes to the action of returning the medium Pto the upstream side in the medium transport direction A. Therefore, aneffective action of separating the medium P can be realized by theretard roller 36 according to the present embodiment to which the roller1 according to the embodiment of the invention is applied.

Embodiment 3 (1) Configuration of Roller (See FIGS. 4 to 18)

As described above, the roller 1A according to the present embodimentincludes the shaft 62, and the elastic body portion 64, and the elasticbody portion 64 is configured to include the inner peripheral portion66, the outer peripheral portion 68, the first connection portion 70,and the second connection portion 72 and the first connection portion 70is inclined in the same direction in the circumferential direction Ewith respect to the radial direction D of the roller 1A.

Specifically, the shaft 62 is bridged over an appropriate support member(for example, upper unit 14) so as to extend horizontally in the axialdirection X. As described above, the elastic body portion 64 has atwo-layered structure including the inner layer portion 74 and the outerlayer portion 76, and the inner peripheral portion 66, the outerperipheral portion 68, the first connection portion 70, and the secondconnection portion 72 which are described above are provided in theinner layer portion 74 among the inner layer portion 74 and the outerlayer portion 76.

The outer layer portion 76 is a cylindrical member having apredetermined thickness in the radial direction D and having apredetermined length in the axial direction X, and on the outerperipheral surface in contact with the medium P, a plurality of annulargroove portions 78 are formed in the axial direction X at apredetermined pitch. In addition, the inner peripheral surface of theouter layer portion 76 is a junction surface with the inner layerportion 74 and is formed by a smooth uniform cylindrical curved surfacein the embodiment illustrated in FIGS. 4 to 9 and FIGS. 12A to 15B.

The inner layer portion 74 includes an inner peripheral portion 66 whichis fitted over the shaft 62 and has a predetermined thickness in theradial direction D and a small diameter having a predetermined length inthe axial direction X. The inner peripheral surface of the innerperipheral portion 66 serves as a fitting surface to be fitted over theshaft 62.

In addition, the inner layer portion 74 includes the outer peripheralportion 68 which is joined to the inner peripheral surface of the outerlayer portion 76, has a predetermined thickness in the radial directionD, and is slightly smaller than the outer layer portion 76 having apredetermined length in the axial direction X. The outer peripheralsurface of the outer peripheral portion 68 is a junction surface to bejoined to the inner peripheral surface of the outer layer portion 76.

The first connection portion 70 is a member for connecting the innerperipheral portion 66 and the outer peripheral portion 68 together withthe second connection portion 72 described below, and in the embodimentillustrated in FIGS. 4 to 9, 8 rectangular plate-shaped members havingthe same length as that of the inner peripheral portion 66 and the outerperipheral portion 68 and having uniform thickness are arranged at equalintervals in the circumferential direction E in a state of beingobliquely inclined as illustrated in the drawings.

In the embodiment illustrated in FIG. 4 and FIG. 7, although a structurein which the first connection portion 70 has a linear shape in a sideview of the roller 1A and is inclined with respect to the radialdirection D from the center of the roller 1A is adopted, the structureis not limited thereto. As will be described below (FIG. 20), astructure in which the first connection portion 70 has a curved shape ina side view of the roller 1A and is inclined with respect to the radialdirection D can also be adopted.

On the other hand, the second connection portion 72 is provided in aspace portion 80 having a triangular or fan-shaped cross-sectional shapeformed between the adjacent first connection portions 70, and isconfigured with a plate-shaped member having a triangular or afan-shaped side surface shape is formed in the axial direction X of theroller 1A partitioning the space portion 80 into the X1 side and theother X2 side as described above in substantially middle position in theaxial direction.

Accordingly, in the roller 1A according to the present embodiment, dueto the presence of the second connection portion 72, the space portion80 is a non-penetrating space portion 80 that does not penetrate in theaxial direction X.

In addition, in the present embodiment, as illustrated in FIGS. 5, 6, 8and 9, the second connection portion 72 is configured to be inclinedwith respect to a surface orthogonal to the axial direction X of theroller 1A, and the adjacent second connection portions 72 (FIGS. 8 and9) via the first connection portion 70 are formed so that theinclination directions are opposite to each other. Therefore, the secondconnection portions 72 partitioning each space portion 80 arranged atequal intervals in the circumferential direction E are adjacent to eachother and the inclination directions thereof are provided so as to bedifferent to each other.

In the embodiments illustrated in FIGS. 5, 6, 8, and 9, although astructure in which the second connection portion 72 has a linear shapein the longitudinal sectional view and is inclined with respect to thesurface is adopted, the structure is not limited thereto. As will bedescribed below (FIG. 21), it is also possible to adopt a structure inwhich the second connection portion 72 has a curved surface in thelongitudinal sectional view and is inclined with respect to the surface.

In addition, in the space portion 80, the second connection portion 72described above is set as a boundary, a recessed portion formed on oneside X1 side in the axial direction X2 of the roller 1A is set as arecessed portion 82 on one side, and the recessed portion formed on theother side X side is set as the recessed portion 84 on the other side.These two recessed portions 82 and 84 are provided so as to have asymmetrical structure as illustrated in the drawings.

In addition, as a constituent material of the elastic body portion 64configured as described above, a non-foamed material is preferable andby adopting the structure including the first connection portion 70 andthe second connection portion 72, the reaction force can be reduced to,for example, 1/10 or less, it is possible to secure a crushed amount ofthe outer peripheral surface of the roller 1A equal to or higher thanthat of the foamed rubber even if using materials of various rubberhardness.

In addition, looking at the relationship between the number ofcompressions and the deformation rate due to the difference inconstituent material of the elastic body portion 64 illustrated in FIG.11, as the number of compressions of the formed rubber increases, thedeformation amount thereof gradually increases and the shape thereofdoes not recover, and regarding this, in a case of A15 elastomer or A20elastomer which is a non-foamed material, it is understood that thedeformation amount thereof is almost constant and the shape thereofrecovers even if the number of compressions thereof increases.

Therefore, from the viewpoint of durability, it can be said that thenon-foamed synthetic rubber or elastomer is more preferable as theconstituent material of the elastic body portion 64 than the foammaterial such as foamed rubber.

In addition, the inclination angle θ1 of the first connection portion 70is desirably 30° or more with respect to the radial direction D of theroller 1A, and 60° illustrated in FIG. 12A, 45° illustrated in FIG. 12B,30° illustrated in FIG. 12C or the like can be adopted to the radialdirection D of the roller 1A. It can be said that 60° thereof is themost practical inclination angle θ1 of the first connection portion 70when considering the size of the reaction force and the like.

In addition, the inclination angle θ2 of the second connection portion72 is desirably 60° or less with respect to the axial direction X of theroller 1A, and 30° illustrated in FIG. 13A, 45° illustrated in FIG. 13B,60° illustrated in FIG. 13C or the like can be adopted to the axialdirection X of the roller 1A. It can be said that 45° thereof is themost practical inclination angle θ2 of the second connection portion 72when considering the size of the reaction force and the like.

In addition, it is preferable that each of the number of the recessedportion 82 on the one side formed on one X1 side in the axial directionX of the roller 1A and the number of the recessed portion 84 on theother side formed on the other X2 side with the second connectionportion 72 as a boundary is 6 or more. Specifically, 6 piecesillustrated in FIG. 14A, 8 pieces illustrated in FIG. 14B, 12 piecesillustrated in FIG. 14C, and the like are included as practical numbersof the recessed portion 82 on the one side and the recessed portion 84on the other side. By all means, the number thereof is not limited tothese numbers.

In addition to this, the shape of the first connection portion 70 isformed to have a uniform thickness from the base end side connected tothe inner peripheral portion 66 to the leading end side connected to theouter peripheral portion 68 as illustrated in FIGS. 4 to 9 and the like,and alternatively, as illustrated in FIG. 15A, it is also possible toadopt a configuration in which the width of the first connection portion70 is changed, such as increasing the thickness on the base end side andreducing the thickness on the leading end side.

In addition, a second space portion 86 is further formed with respect tothe first connection portion 70 illustrated in FIG. 15A, the secondconnection portion 72 is disposed in the middle portion of the secondspace portion 86 in the axial direction X, and it is also possible toadopt an embodiment of a structure in which the recessed portion 82 onthe one side and the recessed portion 84 on the other side are doublyprovided as illustrated in FIG. 15B.

In addition, as a configuration for improving adhesion between the innerlayer portion 74 and the outer layer portion 76, it is possible to adoptvarious junction structures illustrated in FIGS. 16A to 18.Specifically, as illustrated in FIG. 16A, a chamfer 92 is formed on theedges on the one side X1 side and the other side X2 side of the innerperipheral surface of the outer layer portion 76, or the innerperipheral surface of the outer layer portion 76 is roughened asillustrated in FIG. 16B so that fine irregularities 94 can be formed.

In addition, as illustrated in FIG. 16C, primer treatment is applied tothe inner peripheral surface of the outer layer portion 76 before theinner layer portion 74 is insert molded, and an adhesive 96 is appliedto the surface thereof to adhere the inner layer portion 74 and theouter layer portion 76.

In addition, as illustrated in FIGS. 17A, 17B, and 17C, it is possibleto form a groove 98 in the inner peripheral surface of the outer layerportion 76 and the cross-sectional shape of the groove 98 may be atrapezoidal shape illustrated in FIGS. 17A and 17B, a triangular shape,a quadrangular shape, or an undercut shape such as a mushroom shape, adovetail groove shape, or the like having a head portion at the leadingend portion as illustrated in FIG. 17C. In addition, as illustrated inFIG. 17, one groove 98 can be provided, and alternatively, asillustrated in FIGS. 17A and 17C, a plurality of grooves 98 can beprovided.

Further, as illustrated in FIG. 18, a junction structure of a complexconfiguration in which the chamfer 92, the fine irregularities 94, theadhesive 96 and the groove 98 described in FIGS. 16A, 16B, 16C and FIGS.17A, 17B, 17C which are described above can also be adopted.

In addition to this, although not illustrated in the drawings, the firstconnection portion 70 may have a shape extending linearly in a side viewof the roller 1A or alternatively have a shape extending curvedly in aside view thereof. Similarly, the second connection portion 72 may havea shape extending linearly in the longitudinal sectional view, oralternatively, may have a shape extending curvedly in the longitudinalsectional view.

(2) Molding and Action of Roller (Refer to FIGS. 4 to 9, 10, 11 to 18)

In order to mold the roller 1A configured as described above, as anexample, insert molding into which the raw material 90 is poured to befilled can be adopted. FIG. 10 illustrates an aspect of a flow of a rawmaterial 90 of the related art product configured with a through hole 88penetrating the space portion 80 of the roller 1′ in the axial directionX and the present invention product configured with a recessed portion82 on one side and the recessed portion 84 on the other side which doesnot penetrate the space portion 80 of the roller 1A in the axialdirection X is illustrated.

In this case, in the related art product, it is difficult to secure thefluidity of the raw material 90, and the time required until completionof filling is likely to be long. Accordingly, the heat history when theraw material 90 is cured becomes more likely to be changed depending onlocations, and when the final molded product is formed, the outer layerportion 76 of the roller 1′ is deformed and the shape accuracy of theouter peripheral surface of the roller 1′ is likely to decrease.

In contrast, in the present invention product, the fluidity of the rawmaterial 90 is better with the presence of the second connection portion72, and the present invention product is filled with the raw material 90up to every corner and the time required for completion of filling isshortened. Accordingly, the change of the thermal history according tolocations at the time of curing the raw material 90 is reduced, and evenwhen it becomes the final molded product, large deformation is notgenerated at the outer layer portion 76 of the roller 1A, and thus theshape accuracy of the outer peripheral surface of the roller 1Aincreases.

According to the roller 1A of the present embodiment configured asdescribed above, the outer peripheral surface of the roller 1A isstructurally easily crushed not by selection of materials, and the areaof the contact surface S can be enlarged.

In other words, when a pressing force F directed toward the center ofthe roller 1A is applied by pressing the roller 1A against the medium P,a force (shearing) which is parallel to the pressing direction and whichis the opposite direction acts on both the portions of a connectionportion Ji with the inner peripheral portion 66 of the first connectionportion 70 and the connection portion Jo with the outer peripheralportion 68 thereof. In this case, since both the first connectionportion 70 and the second connection portion 72 are elastic bodies, thefirst connection portion 70 and the second connection portion 72 swingabout the connection portions Ji and Jo of the inner peripheral portion66 and the outer peripheral portion 68 as a supporting point, andalternatively can also shrink in the longitudinal direction which is theextending direction thereof. By this behavior, a good crush of the outerperipheral surface of the roller 1A described above is realized.Further, by reversing the inclination directions of the adjacent secondconnection portions 72, the mutual swinging cancels each other, so thatshrinkage deformation in the longitudinal direction is generatedexclusively and the outer peripheral surface of the roller 1A can becrushed in a well-balanced manner.

Embodiment 4 (1) Configuration of Roller (See FIG. 19)

In the roller 1B according to the present embodiment, the roller 1Aaccording to the third embodiment is configured with two members of theinner layer portion 74 and the outer layer portion 76, whereas the outerlayer portion 76 of the separate member is eliminated, and the innerlayer portion 74 is configured with a single member having the functionof the outer layer portion 76.

Therefore, since the other constitution is the same as that ofEmbodiment 3, here, the same configuration as that of Embodiment 3 willbe briefly explained or explanation thereof will be omitted and theunique configuration of the roller 1B according to the presentembodiment will be mainly described.

In other words, the roller 1B according to the present embodiment, likethe roller 1A according to Embodiment 3, includes a shaft 62 and anelastic body portion 64 and the elastic body portion 64 is configured byincluding an inner peripheral portion 66, an outer peripheral portion68, a first connection portion 70, and a second connection portion 72.

The first connection portion 70 is inclined in the same direction in thecircumferential direction E with respect to the radial direction D ofthe roller 1B, and the elastic body portion 64 is configured with asingle member.

Accordingly, in the roller 1B according to the present embodiment, aplurality of annular groove portions 78 formed on the outer peripheralsurface of the outer layer portion 76 in Embodiment 3 are formed withrespect to the outer peripheral surface of the single-member elasticbody portion 64.

In addition, as for the modification example in which the constituentmaterial of the elastic body portion 64, the shape, number, angle, andarrangement of the first connection portion 70 and the second connectionportion 72 are made different, the ones described in Embodiment 3 can beadopted as it is.

(2) Molding and Action of Roller

In order to mold the roller 1B configured as described above, injectionmolding, in which the heated and softened raw material 90 is pushed intoa closed mold, cooled, solidified, and molded, can be adopted as anexample. Also, in this case, the effect illustrated in FIG. 10 describedin Embodiment 3 can be obtained, large deformation is not generated onthe outer peripheral surface of the roller 1B, and the shape accuracy ofthe outer peripheral surface of the roller 1B is improved.

Also in the present embodiment, like Embodiment 3, the outer peripheralsurface of the roller 1B can be structurally easily crushed in awell-balanced manner not by selection of materials, and the contact areawith the medium P can increase.

OTHER EMBODIMENTS

Although the roller 1, the separation device 60, and the image readingapparatus 10 according to the embodiment of the invention are based onthe configuration as described above, the partial configuration withoutdeparting from the gist of the invention, can naturally change, omit,apply to other devices, or the like.

FIG. 20 is a side view illustrating a roller according to anotherembodiment of the invention. In the embodiment described above, althoughthe first connection portion 70 has been described as a structure havinga linear shape in a side view of the roller 1A and being inclined withrespect to the radial direction D from the center of the roller 1A, asillustrated in FIG. 20, a structure in which the first connectionportion 70 has a curved shape in a side view and is inclined withrespect to the radial direction D of the roller 1 can be adopted. Sincethe other structure is the same as that of the embodiment describedabove, description thereof will be omitted.

By making the first connection portion 70 into the curved shape, it ispossible to realize the crush of the roller 1 when the pressing force Fis applied to the roller 1 in a more well-balanced manner.

Although the structure in which the roller 1 does not have the outerlayer portion 76 is illustrated here, it is a matter of course that theroller 1 is not limited to this structure and may have a structureincluding the outer layer portion 76.

FIG. 21 is a longitudinal sectional view illustrating a roller accordingto still another embodiment of the invention. Here, although thestructure in which the roller 1 does not have the outer layer portion 76is illustrated, it is a matter of course that the structure is notlimited to this structure and a structure having the outer layer portion76 may also be adopted. In the embodiment described above, although thesecond connection portion 72 is described as a structure having a linearshape in the longitudinal sectional view and being inclined with respectto the surface, as illustrated in FIG. 21, the second connection portion72 can also adopt a structure in which the longitudinal sectional viewhas a curved shape and is inclined with respect to the surface may beadopted. Since the other structure is the same as that of the embodimentdescribed above, description thereof will be omitted.

By making the second connection portion 72 into the curved shape, it ispossible to realize the crush of the roller 1 when the pressing force Fis applied to the roller 1 in a more well-balanced manner.

Although the structure in which the roller 1 does not have the outerlayer portion 76 is illustrated here, it is a matter of course that theroller 1 is not limited to this structure and may have a structureincluding the outer layer portion 76.

In addition, the roller 1 of the embodiment according to the inventionas described above and the separation device 60 applying the roller 1 tothe retard roller 36 can be applied to a recording apparatus thatexecutes recording on the medium P. In other words, the recordingapparatus according to the embodiment of the invention is an ink jetprinter or the like including a recording portion such as a recordinghead, and a roller that is provided in a medium transport path 26passing through the recording execution region of the recording portionto apply a feeding force to the medium P, in which the roller has astructure in which the contact surface S is elastically crushed whenpressed against the medium P and at least one of the rollers, forexample, the retard roller 36 can be configured with the roller 1 of theembodiment according to the invention.

In addition, the thickness of the inner peripheral portion 66 and theouter peripheral portion 68 can also be appropriately adjusted within arange where necessary rigidity and elasticity can be obtained. Inaddition to this, in the shapes of the side view of the first connectionportion 70 and the longitudinal sectional view of the second connectionportion 72, various shapes of which the pressing direction describedabove is parallel and an opposite force (shearing) can be obtained, and,in addition to the shape described in the embodiment described above, itmay be a shape bent in one stage or in multi-stages or a branched shapein the middle thereof.

The entire disclosure of Japanese Patent Application No. 2017-079505,filed Apr. 13, 2017, and 2017-079506, filed Apr. 13, 2017 are expresslyincorporated by reference herein.

What is claimed is:
 1. A roller comprising: a shaft; and an elastic bodyportion that is provided on an outer peripheral surface of the shaft,wherein the elastic body portion includes an inner peripheral portionwhich becomes a shaft side, an outer peripheral portion which becomes anouter side with respect to the inner peripheral portion, a plurality offirst connection portions which connect the inner peripheral portion andthe outer peripheral portion, and a plurality of second connectionportions which are provided in a space portion between the adjacentfirst connection portions to each other and which partition the spaceportion into one side and the other side of the roller in a shaftmounting direction, and wherein the first connection portion is inclinedin the same direction in a circumferential direction with respect to aradial direction of the roller.
 2. The roller according to claim 1,wherein the second connection portion is inclined with respect to asurface orthogonal to the shaft mounting direction of the roller, andwherein inclination directions of adjacent second connection portions toeach other via the first connection portion are opposite to each other.3. The roller according to claim 2, wherein a recessed portion on oneside that can be formed on one side of the roller in the shaft mountingdirection and the recessed portion on the other side that can be formedon the other side with the second connection portion as a boundary areformed so as to be symmetrical with respect to a center surfaceorthogonal to the shaft mounting direction.
 4. The roller according toclaim 1, wherein the constituent material of the elastic body portion isa non-foamed material.
 5. The roller according to claim 1, wherein theelastic body portion includes an inner layer portion that becomes theshaft side, and an outer layer portion that becomes a side which is incontact with the medium, and wherein the inner layer portion includesthe first connection portion, the second connection portion, the innerperipheral portion, and the outer peripheral portion.
 6. The rolleraccording to claim 1, wherein an inclination angle of the firstconnection portion which connects the inner peripheral portion and theouter peripheral portion to each other is 30° or more with respect tothe radial direction of the roller.
 7. The roller according to claim 1,wherein an inclination angle of the second connection portion is 60° orless with respect to the axial direction of the roller.
 8. The rolleraccording to claim 1, wherein the numbers of the recessed portion on theone side that can be formed on one side in the axial direction of theroller and the recessed portion on the other side that can be formed onthe other side with the second connection portion as a boundary are 6 ormore, respectively.
 9. A separation device comprising: a feeding roller;and a retard roller that forms a pair with the feeding roller, separatesmedia other than a medium to be transported from a bundle of media, andreturns the media to an upstream side, wherein the retard roller is theroller according to claim
 1. 10. A separation device comprising: afeeding roller; and a retard roller that forms a pair with the feedingroller, separates media other than a medium to be transported from abundle of media, and returns the media to a upstream side, wherein theretard roller is the roller according to claim
 2. 11. A separationdevice comprising: a feeding roller; and a retard roller that forms apair with the feeding roller, separates media other than a medium to betransported from a bundle of media, and returns the media to an upstreamside, wherein the retard roller is the roller according to claim
 3. 12.A separation device comprising: a feeding roller; and a retard rollerthat forms a pair with the feeding roller, separates media other than amedium to be transported from a bundle of media, and returns the mediato an upstream side thereof, wherein the retard roller is the rolleraccording to claim
 4. 13. A separation device comprising: a feedingroller; and a retard roller that forms a pair with the feeding roller,separates media other than a medium to be transported from a bundle ofmedia, and returns the media to an upstream side thereof, wherein theretard roller is the roller according to claim
 5. 14. A separationdevice comprising: a feeding roller; and a retard roller that forms apair with the feeding roller, separates media other than a medium to betransported from a bundle of media, and returns the media to an upstreamside thereof, wherein the retard roller is the roller according to claim6.
 15. A separation device comprising: a feeding roller; and a retardroller that forms a pair with the feeding roller, separates media otherthan a medium to be transported from a bundle of media, and returns themedia to an upstream side thereof, wherein the retard roller is theroller according to claim
 7. 16. A separation device comprising: afeeding roller; and a retard roller that forms a pair with the feedingroller, separates media other than a medium to be transported from abundle of media, and returns the media to an upstream side thereof,wherein the retard roller is the roller according to claim
 8. 17. Theseparation device according to claim 9, wherein an inclination directionof the first connection portion is formed such that, when the rollerreceives a pressing force from the medium, a swinging direction with theconnection portion with the inner peripheral portion of the firstconnection portion as a supporting point becomes a direction ofreturning the medium to the upstream side.
 18. An image readingapparatus comprising: a reading portion that reads image information ofa medium; and a roller that is provided in a medium transport path whichpasses through a reading execution region of the reading portion andthat applies a feeding force to the medium, wherein the roller has astructure in which a contact surface between the roller and the mediumis elastically crushed when the roller is pressed against the medium,and wherein at least one of the rollers is the roller according toclaim
 1. 19. An image reading apparatus comprising: a reading portionthat reads image information of a medium; and a roller that is providedin a medium transport path which passes through a reading executionregion of the reading portion and that applies a feeding force to themedium, wherein the roller has a structure in which a contact surfacebetween the roller and the medium is elastically crushed when the rolleris pressed against the medium, and wherein at least one of the rollersis the roller according to claim
 2. 20. A recording apparatuscomprising: a recording portion; and a roller that is provided in amedium transport path passing through a recording execution region ofthe recording portion and applies a feeding force to the medium, whereinthe roller has a structure in which a contact surface thereof iselastically crushed when pressed against the medium, and wherein atleast one of the rollers is the roller according to claim 1.